Abstract: A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market. It is produced by treating natural resin (amber or copal) with heat and pressure in two stages in an autoclave. Differences in molecular structure between untreated amber and copal as compared to treated “green amber” were studied by FTIR and 13C NMR spectroscopy, using powdered samples. Regardless of the starting material, the FTIR spectrum of “green amber” showed an amber pattern but with a characteristic small absorption feature at 820 cm-1. Solid-state 13C NMR spectroscopy of the treated material indicated a significantly lower volatile component than in the untreated natural resin, evidence that the treatment can actually “artificially age” copal. A new absorption observed near 179 ppm in the NMR spectra of all the treated samples also separated them from their natural-color counterparts.

We had fun selling and buying specimens at the gem show. If you missed it, here are some of the things you can expect to find at a show.

An overview of the whole show. Photo by Stephanie Reed

This year we sold books about rocks and where to find them, including the highly desired Gemstones of North America by John Sinkankas.

Mark selling minerals.

President Martin and Webmistress Stephanie looking at an aquamarine. Photo by David Reed

This jar of tumbled chips of Lake Superior agates was part of a kit for making a gem tree, sold by the Show-Me Rockhounds. Photo by Stephanie Reed

Polished spheres made of minerals from Dave’s Rocks and Carvings (Hamburg, MI). I see rose quartz, tiger’s eye, sodalite, and snowflake obsidian. Can you name all the minerals?

Mineral specimens for sale from Dave’s Rocks and Carvings (Hamburg, MI) Photo by David Reed

Gem shows always have lots of jewelry for sale, usually organized by mineral. This is an entire box full of rings made with blue larimar sold by Manichia LLC (Kansas City, MO). Blue larimar is a type of volcanic pectolite found in the Dominican Republic.

Glass beads for sale at Park Design (St. Joseph, MO). You can even watch the beads being made. They can also be found at the Three Trails Trading Post in Independence, MO.

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